# LCM & HCF YouTube Lecture Handouts

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HCF and LCM - 3 Speed Tricks & 10 Typical Word Problems

## LCM & HCF Story with Tree & Circles

Mayank explains the following two key concepts to quickly and easily identify and solve all HCF and LCM problems - 1. Quickly find HCF and LCM using 3 simple tricks in this video.2. To detect HCF and LCM word problems, use the following keywords:**LCM**1. Minimum number of days, rounds etc. 2. Least amount of time, things etc. 3. Smallest number, length, amount of time etc.**HCF**1. Maximum (possible) number of days, things etc. 2. Longest (possible) size, length, amount of time etc.

## Our Journey

Factors

Prime Factors

Multiples

Factors and Multiples

Highest Common Factor

Common Factors

Least Common Multiple

Common Multiples

**Understanding Factors**

## Prime Factors

Factors which are prime (numbers) are called prime factors

## Understanding Multiples

## Factors and Multiples

*Factors*can (completely)*divide*the number

< Number

*Multiples*are (completely)*divisible*by the number.

> Number

## Factorization Using Tree of Factors

## Tree of Factors- 24

## Common Factors of 32 and 24

## Finding Common Factors (HCF) Using Grouping

Common Multiples of 32 and 24

32 --- 32, 64, 96, 128, 160, 192, 224,…

24 --- 24, 48, 72, 96, 120, 144, 168, 192,…

Least Common Multiple - LCM

Lowest common Factor – LCM

Highest Common Multiple - HCH

## HCF and LCM Combining the Two Steps

## Other Names of HCF

Greatest Common Factor - GCF

Greatest Common Divisor - GCD

Why Prime Factors?

-Mayank